Sure, but those activities typically won't last for hours. I've had to put tasks on hold because the SME wasn't available for several hours, without explanation or any communication whatsoever, to make a fundamental design decision in their area of expertise. And it wasn't a one-off or just one SME. People, at least my team, were getting constantly distracted. They essentially imposed their irregular and unpredictable schedules on the rest of us, despite being in positions of relative authority. I had to work nights I didn't plan to work because someone decided to respond at 8pm to a question asked at 1pm. That kind of delay would never happen at the office even if someone was slacking off.
Which goes back to the principle that WFH is more beneficial for senior devs than juniors. If you lack the knowledge or authority to work independently for extended periods, then instead of everyone being on the same objective schedule the junior people are forced onto whenever the senior people want to work, and more specifically when they want to be available to answer questions that only they can answer. It's like only being able to do homework during a professor's office hours.
Which goes back to the principle that WFH is more beneficial for senior devs than juniors. If you lack the knowledge or authority to work independently for extended periods, then instead of everyone being on the same objective schedule the junior people are forced onto whenever the senior people want to work, and more specifically when they want to be available to answer questions that only they can answer. It's like only being able to do homework during a professor's office hours.